Programmable logic devices (“PLDs”) exist as a well-known type of integrated circuit (“IC”) that may be programmed by a user to perform specified logic functions. There are different types of programmable logic devices, such as programmable logic arrays (“PLAs”) and complex programmable logic devices (“CPLDs”). One type of programmable logic device, called a field programmable gate array (“FPGA”), is very popular because of a superior combination of capacity, flexibility, time-to-market, and cost.
An FPGA typically includes an array of configurable logic blocks (“CLBs”) and programmable input/output blocks (“IOBs”). The CLBs and IOBs are interconnected by a programmable interconnect structure. The CLBs, IOBs, and interconnect structure are typically programmed by loading a stream of configuration data (“bitstream”) into internal configuration memory cells that define how the CLBs, IOBs, and interconnect structure are configured. CLBs and IOBs form the programmable part of an FPGA referred to as the “FPGA fabric”, which is subject to program control of the configuration memory cells. FPGAs may also contain other types of known circuitry.
In order to ensure operability, an FPGA is tested prior to release to customers. Accordingly, it would be desirable and useful to provide design verification using test patterns prior to product release.